low pressure fuel pump error code

[BUDFORCE]

Well got the car back, guy said he'd done 10 miles on it and running ok, all fault codes gone. I drove it back just now although literally 2 minutes.

Hopefully it was the fuel pump module. I can't see any obvious signs of failure (ignore the damage around the edges where I have tried and failed to pry it up) but time will tell.....

 

[BUDFORCE]

.........and the same warning light is back........

Now I'm pretty concerned. It doesn't "feel" like there is anything wrong with the fuel pump, the car is driving flawlessly.

Which is now got me thinking there is some electrical issue somewhere. I'm gonna get it back in the garage and and see what they say but new fuel pump will be a £1000 job and I'm quite concerned it won't fix the issue.

FFS.....

 

[BUDFORCE]

Your OP suggests you have access to diagnostics, go for a drive with a graph of Desired Fuel Pressure, Actual Fuel Pressure and "Fuel Pump Command" (name varies).

When the disco pump was dying, the actual lagged behind desired further and further until the pump flat out stopped spinning. Leaving it for an hour brought it back to life for a while, until it did the same

It's not a full one, I got an icarsoft vol2, which is about the only off the shelf DIY one you can get before obtaining the DICE software through gray sources etc.

It can monitor those, although the graph is pretty basic and I'd only be able to see one at a time.

 

[BUDFORCE]

how quickly does the light come on after the incident, or does log give exact time so that you could know exactly what you were doing on the throttle at the time
(do you havee dashcam to remind you)

Just comes on straight when you fire it up.

I cleared it yesterday, left the car a few hours, fired it up again and once again just comes straight on at startup, or I guess the engine warning light doesn't go away when you start the engine which is a more accurate description.

I've dropped it back in the garage now they are gonna take another look at it, it drove absolutely fine, revved the engine pretty high.

I'm worried about it being some dodgy wiring or similar, although I am trying to think if the voltage is too high, would that get caused by a bad connection? I would have thought it might be the other way around, if it was grounding the voltage would drop not get higher???

Anyway, see what they say this time, it's above my pay grade and free time to try and fix this now. I guess if I bought another car and had it sitting there as a project car and could leave it in bits, I could try go around all the wiring with a meter, but I don't have that luxury at the moment.

 

[BUDFORCE]

you hadn't had the sensor changed had you ? so maybe it coincidentally has a problem like the replaced pump control unit ..
or, perhaps it had conributed to pump control unit failure by using pump contol unit (& pump) too much / unecessarily

had you done a few hyndred successful miles since the control unit was replaced.

Yea the sensor got changed same time as the control module.

And no hardly done any miles, basically after I picked it up week before I drove it twice, once literally a mile, then about 5 miles. Both journeys fine, no error code.

Then it sat for a week. Then when I started it up yesterday, warning light straight back on, same fault code as I was getting before it broke down. Cleared the code, waited few hours, started it again, code straight back on again. I did drive it about 5 miles yesterday, with the error code on, car drove absolutely fine, then again another mile today back to the garage.

 

[BUDFORCE]

was it an oem sensor (I purchased what I thought was an oem brake servo sensor from amazon, which they subsequently refunded because it was a knock-off,
but it's working so far - but had wondered about getting a genuine one too)

Nah unbranded.

I'm struggling to believe though that would also be faulty and create the exact same symptoms, although I guess it's possible....

 

[BUDFORCE]

Well.............

Turns out my initial diagnosis of dodgy low pressure fuel sensor was correct.......

However, the sensor I bought to replace the dodgy sensor, was dodgy, ffs........

As above I would have not bet on that.

Anyway, lesson learned here, make sure you get get good quality/genuine sensors. I cant say I have ever had an issue before this was the first time, but I guess when you are dealing with a fuel system that has something like 8 separate components working together, buying a cheap sensor doesn't necessarily eliminate the problem, and on this occasion created a rabbit hole that never needed to be......

At least its sorted now.